PD239 - EARLY CHANGES IN QUADRICEPS MUSCLE THICKNESS IN CRITICALLY ILL PATIENTS

PD239

EARLY CHANGES IN QUADRICEPS MUSCLE THICKNESS IN CRITICALLY ILL PATIENTS

V. A. Fugas^1,2,*, V. A. te^1,2, C. A. Zucchella², P. Astegiano^1,2, N. I. Carrizo²

¹Unidad de Soporte Nutricional, ²Unidad de Terapia Intensiva, Hospital Dr. J.M. Cullen, Santa Fe, Argentina

Rationale: Muscle loss is a hallmark of critical illness and occurs early during ICU stay. Bedside ultrasound enables serial assessment of muscle thickness in critically ill patients.

Methods: Prospective observational study (Argentina, May–July 2025) including adult ICU patients requiring mechanical ventilation >48 h. Quadriceps muscle layer thickness (QMLT) assessed at ICU admission (days 1–3) and follow-up (days 6–10) using standardized protocol. Patients with both measurements and informed consent were included. Absolute and relative QMLT changes were calculated, and the daily percentage rate of change was estimated, adjusted for time between measurements. Continuous variables are presented as mean ± SD or median (IQR). Non-parametric tests and Spearman correlation were used. A p<0.05 was considered statistically significant.

Results: Of 42 patients, 61.9% were male, median age was 44 years (IQR 27–55) and BMI of 23.9 kg/m² (IQR 21–27). Malnutrition (GLIM) was present in 52.4%. Baseline QMLT was 2.97 ± 1.06 cm. Median ICU and hospital length of stay were 18 (IQR 11–27) and 28 days (IQR 14–53), respectively. Median muscle loss was 15.22% (IQR 2.96–21.83), with marked interindividual variability. Eight patients (19%) showed an apparent increase in QMLT, likely related to changes in fluid shifts. Median time between measurements was 5 days (IQR 4–8). The median daily percentage rate of change, adjusted for time between measurements, was 2.15% (IQR 0.74–5.22). Age was positively correlated with muscle loss (ρ=0.313, p=0.044), with no significant associations observed with other clinical variables.

Conclusion: Quadriceps muscle loss in critically ill patients is early, rapid, and highly heterogeneous, reaching clinically relevant magnitude within the first week of ICU stay. Increasing age may predispose to greater muscle loss. These findings support the need to consider individual trajectories of muscle change during critical illness.

Disclosure of Interest: V. Fugas Grant / Research Support from: ESICM fellowship 2024 sponsored by Fresenius Kabi, Speakers Bureau of: Invited speaker for a Fresenius Kabi webinar (2025), V. te: None declared, C. Zucchella: None declared, P. Astegiano: None declared, N. Carrizo: None declared